The computer store by the A computer system at the cost of $574.50 the selling price was first $891 but then the storage adverti
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As per the problem,
The larger pump takes 40 minutes to fill the pool.
The smaller one takes 60 minutes.
When both the pumps are working , let the time taken be x minutes , then we can write
Hence, when both the pumps works together, Time taken =24 minutes.
Answer:
So on this case the 95% confidence interval would be given by (23.9;32.1)
Step-by-step explanation:
Previous concepts
A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".
The margin of error is the range of values below and above the sample statistic in a confidence interval.
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
represent the sample mean
population mean (variable of interest)
s=10 represent the sample standard deviation
n=25 represent the sample size
Solution to the problem
The confidence interval for the mean is given by the following formula:
(1)
In order to calculate the critical value we need to find first the degrees of freedom, given by:
Since the Confidence is 0.95 or 95%, the value of and
, and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.025,24)".And we see that
Now we have everything in order to replace into formula (1):
So on this case the 95% confidence interval would be given by (23.9;32.1)